The main reasons I do not like is the involvement of a HOA and many of them are built like well-fished apartments. 

Mainly being sarcastic lol.  

My main concerns are splitting bills, mail, and AC temp (only 1 AC unit).

Is it still possible for me to do Brrrr or I have to mainly look at good cash flow deals?

We've had the poo (and the pee): dog poo, alpaca poo, cat pee, and main sewer stack replacements.

My main thing is the financing?

.), thinking of buying another investment property (mainly for long term investment and tax benefits), any recommendations? 

Of course, your main hurdle is your location.

You can give the account an internal "nickname" (2302 Main St deposit) as a reminder of what it's for.

The main thing of course is to be aware of and follow all the additional tenant protection ordinances that seattle has which go a lot further than WA state landlord tenant law does.Seattle has a just cause eviction law ,    additional categories of 'protected class' that you cannot discriminate against,  there are rules around what you can and cannot consider when doing screenings  (you cannot consider most criminal history for example),   and there are rules forcing you for example to accept a six month interest free payment plan for deposit and last months rent if the applicant requests it.